Car with 20+ USB outlets and multiple device charging

I was traveling in Japan and a taxi used 20+ USB outlets, mobile wifi and multiple device charging.

He upgraded the wire from the battery so it could handle all the devices. He had two wires from the battery. The regular wire to the charger was not good enough. Each gadget draws perhaps 2 amps he was using almost 30 outlets. 40-60 Amps of toal fuses would be enough to handle them (and their spiking current demands when you first plug them in or turn them on).